A flow cell optosensor for determination of Co(II) based on immobilised 2-(4-pyridylazo)resorcinol in chitosan membrane by using stopped flow, flow injection analysis

A flow cell optosensor, for the determination of Co(II), was developed in this study based on 2-(4-pyridylazo)resorcinol (PAR) immobilised in chitosan membrane as a transducer. This transducer was incorporated to the distal end of a bifurcated optical fibre, which, on the other hand, was connected to a stopped flow FIA instrumentation. An optimum response was obtained at pH 7.0. The sensor produced a linear response for Co(II) concentration range of 1.0×10−3 to 1.0×104 ppm with detection limit of 7.9×10−6 ppm. The calculated relative standard deviation (R.S.D.) of the repeatability and reproducibility of the method are 1.6 and 5.8%, respectively. The sensor can be regenerated by using a mix solution of HCl (0.2 M) and saturated KCl. Interference from foreign ions was also studied at 1:1 mole ratio of Co(II):foreign ions.